lib: support splitting mail from database location.

Introduce a new configuration value for the mail root, and use it to
locate mail messages in preference to the database.path (which
previously implied the mail messages were also in this location.

Initially only a subset of the CLI is tested in a split
configuration. Further changes will be needed for the remainder of the
CLI to work in split configurations.

doc/man1/notmuch-config.rst

@@ -43,13 +43,22 @@ configuration file and corresponding database.
 The available configuration items are described below.
 
 **database.path**
-    The top-level directory where your mail currently exists and to
-    where mail will be delivered in the future. Files should be
-    individual email messages. Notmuch will store its database within
-    a sub-directory of the path configured here named ``.notmuch``.
+    Notmuch will store its database here, (in
+    sub-directory named ``.notmuch`` if **database.mail\_root**
+    is unset).
 
     Default: ``$MAILDIR`` variable if set, otherwise ``$HOME/mail``.
 
+**database.mail_root**
+    The top-level directory where your mail currently exists and to
+    where mail will be delivered in the future. Files should be
+    individual email messages.
+
+    History: this configuration value was introduced in notmuch 0.32.
+
+    Default: For compatibility with older configurations, the value of
+    database.path is used if **database.mail\_root** is unset.
+
 **database.hook_dir**
 
     Directory containing hooks run by notmuch commands. See

lib/config.cc

@@ -406,6 +406,8 @@ _notmuch_config_key_to_string (notmuch_config_key_t key)
     switch (key) {
     case NOTMUCH_CONFIG_DATABASE_PATH:
 	return "database.path";
+    case NOTMUCH_CONFIG_MAIL_ROOT:
+	return "database.mail_root";
     case NOTMUCH_CONFIG_HOOK_DIR:
 	return "database.hook_dir";
     case NOTMUCH_CONFIG_EXCLUDE_TAGS:
@@ -428,7 +430,7 @@ _notmuch_config_key_to_string (notmuch_config_key_t key)
 }
 
 static const char *
-_notmuch_config_default (void *ctx, notmuch_config_key_t key)
+_notmuch_config_default (notmuch_database_t *notmuch, notmuch_config_key_t key)
 {
     char *path;
 
@@ -436,11 +438,14 @@ _notmuch_config_default (void *ctx, notmuch_config_key_t key)
     case NOTMUCH_CONFIG_DATABASE_PATH:
 	path = getenv ("MAILDIR");
 	if (path)
-	    path = talloc_strdup (ctx, path);
+	    path = talloc_strdup (notmuch, path);
 	else
-	    path = talloc_asprintf (ctx, "%s/mail",
+	    path = talloc_asprintf (notmuch, "%s/mail",
 				    getenv ("HOME"));
 	return path;
+    case NOTMUCH_CONFIG_MAIL_ROOT:
+	/* by default, mail root is the same as database path */
+	return notmuch_database_get_path (notmuch);
     case NOTMUCH_CONFIG_EXCLUDE_TAGS:
 	return "";
     case NOTMUCH_CONFIG_NEW_TAGS:

lib/database.cc

@@ -1350,7 +1350,7 @@ _notmuch_database_relative_path (notmuch_database_t *notmuch,
     const char *db_path, *relative;
     unsigned int db_path_len;
 
-    db_path = notmuch_database_get_path (notmuch);
+    db_path = notmuch_config_get (notmuch, NOTMUCH_CONFIG_MAIL_ROOT);
     db_path_len = strlen (db_path);
 
     relative = path;

lib/message-file.c

@@ -64,7 +64,7 @@ _notmuch_message_file_open_ctx (notmuch_database_t *notmuch,
     if (unlikely (message == NULL))
 	return NULL;
 
-    const char *prefix = notmuch_database_get_path (notmuch);
+    const char *prefix = notmuch_config_get (notmuch, NOTMUCH_CONFIG_MAIL_ROOT);
 
     if (prefix == NULL)
 	goto FAIL;

lib/message.cc

@@ -1102,7 +1102,7 @@ _notmuch_message_ensure_filename_list (notmuch_message_t *message)
 
 	*colon = '\0';
 
-	db_path = notmuch_database_get_path (message->notmuch);
+	db_path = notmuch_config_get (message->notmuch, NOTMUCH_CONFIG_MAIL_ROOT);
 
 	directory = _notmuch_database_get_directory_path (local,
 							  message->notmuch,

lib/notmuch.h

@@ -2474,6 +2474,7 @@ notmuch_config_list_destroy (notmuch_config_list_t *config_list);
 typedef enum _notmuch_config_key {
     NOTMUCH_CONFIG_FIRST,
     NOTMUCH_CONFIG_DATABASE_PATH = NOTMUCH_CONFIG_FIRST,
+    NOTMUCH_CONFIG_MAIL_ROOT,
     NOTMUCH_CONFIG_HOOK_DIR,
     NOTMUCH_CONFIG_EXCLUDE_TAGS,
     NOTMUCH_CONFIG_NEW_TAGS,

lib/open.cc

@@ -263,6 +263,11 @@ _choose_xapian_path (void *ctx, const char *database_path, const char **xapian_p
     if (status)
 	goto DONE;
 
+    trial_path = talloc_asprintf (ctx, "%s/xapian", database_path);
+    status = _trial_open (trial_path, message_ptr);
+    if (status != NOTMUCH_STATUS_PATH_ERROR)
+	goto DONE;
+
     notmuch_path = talloc_asprintf (ctx, "%s/.notmuch", database_path);
     status = _db_dir_exists (notmuch_path, message_ptr);
     if (status)

test/T055-path-config.sh

@@ -0,0 +1,90 @@
+#!/usr/bin/env bash
+test_description='Configuration of mail-root and database path'
+. $(dirname "$0")/test-lib.sh || exit 1
+
+backup_config () {
+    local test_name=$(basename $0 .sh)
+    cp ${NOTMUCH_CONFIG} notmuch-config-backup.${test_name}
+}
+
+restore_config () {
+    local test_name=$(basename $0 .sh)
+    export NOTMUCH_CONFIG="${TMP_DIRECTORY}/notmuch-config"
+    unset CONFIG_PATH
+    unset DATABASE_PATH
+    unset NOTMUCH_PROFILE
+    cp notmuch-config-backup.${test_name} ${NOTMUCH_CONFIG}
+}
+
+split_config () {
+    local dir
+    backup_config
+    dir="$TMP_DIRECTORY/database.$test_count"
+    rm -rf $dir
+    mkdir $dir
+    notmuch config set database.path $dir
+    notmuch config set database.mail_root $MAIL_DIR
+    DATABASE_PATH=$dir
+}
+
+
+
+for config in traditional split; do
+    # start each set of tests with a known set of messages
+    add_email_corpus
+
+    case $config in
+	traditional)
+	    backup_config
+	    ;;
+	split)
+	    split_config
+	    mv mail/.notmuch/xapian $DATABASE_PATH
+	    ;;
+    esac
+
+    test_begin_subtest "count ($config)"
+    output=$(notmuch count '*')
+    test_expect_equal "$output" '52'
+
+    test_begin_subtest "count+tag ($config)"
+    tag="tag${RANDOM}"
+    notmuch tag +$tag '*'
+    output=$(notmuch count tag:$tag)
+    notmuch tag -$tag '*'
+    test_expect_equal "$output" '52'
+
+    test_begin_subtest "address ($config)"
+    notmuch address --deduplicate=no --sort=newest-first --output=sender --output=recipients path:foo >OUTPUT
+    cat <<EOF >EXPECTED
+Carl Worth <cworth@cworth.org>
+notmuch@notmuchmail.org
+EOF
+    test_expect_equal_file EXPECTED OUTPUT
+
+    test_begin_subtest "dump ($config)"
+    notmuch dump is:attachment and is:signed | sort > OUTPUT
+    cat <<EOF > EXPECTED
+#notmuch-dump batch-tag:3 config,properties,tags
++attachment +inbox +signed +unread -- id:20091118005829.GB25380@dottiness.seas.harvard.edu
++attachment +inbox +signed +unread -- id:20091118010116.GC25380@dottiness.seas.harvard.edu
+EOF
+    test_expect_equal_file EXPECTED OUTPUT
+
+    test_begin_subtest "dump + tag + restore ($config)"
+    notmuch dump '*' > EXPECTED
+    notmuch tag -inbox '*'
+    notmuch restore < EXPECTED
+    notmuch dump > OUTPUT
+    test_expect_equal_file EXPECTED OUTPUT
+
+    test_begin_subtest "reindex ($config)"
+    notmuch search --output=messages '*' > EXPECTED
+    notmuch reindex '*'
+    notmuch search --output=messages '*' > OUTPUT
+    test_expect_equal_file EXPECTED OUTPUT
+
+    restore_config
+done
+
+test_done

test/T590-libconfig.sh

@@ -364,6 +364,7 @@ EOF
 cat <<'EOF' >EXPECTED
 == stdout ==
 MAIL_DIR
+MAIL_DIR
 MAIL_DIR/.notmuch/hooks
 
 inbox;unread